Oxy torch to heat the base?

I'm with Dave and Bernard, oxy/propane or a large propane blow torch. You may have to get it near red heat to break the rust. Or light a bonfire of wood, old pallets in the garden and set it in the middle. Good luck. Noel.

Hi, before I read Noel's post, I was thinking about heating it on a bonfire, but I'd build the bonfire first and then set the base on top and the light the bonfire, to gradually raise the temperature, instead of sudden heat. Once it got burning you can then add more wood, until you think it's hot enough, and then let the bonfire burn itself out and allow it all to cool down in the ashes, but you may have to it a dull red heat to do any good. When it's cool enough, pour a good deal of penetrating oil in that hole in the bottom and in those grub screw holes.

Regards Nick.

Edited By Nicholas Farr on 30/07/2023 15:35:41

Re your second picture Martin. I can see the moving part of the press (bottle jack) is presumably pushing on the crescent shaped access to the bottom of the pillar, but what is in contact with the top (RH in picture) of the base casting?

I would suggest that you apply several tons force to the bottom of the tube to 'load up' the whole assembly, then use a lead mallet to 'shock' the rust into submission. Hitting radially around the tubular part whilst loaded will be beneficial.

Are you able to also apply a shock force axially by using a drift and hammer on the end of the tube as well (if there is access past the jack spreader plate).

Whilst heat (a lot of very hot heat!) would help, I foresee some issues with the practicality of manhandling something so heavy and too hot to touch. It is not as if its just going to slide out so you would still need the press, whilst its hot!

Ian P

You could drastically reduce the amount of times you need to move it by using more modern paint; if you use ordinary 2k paint from an automotive supplier, you won't need the undercoat, acid, neutralising or rubbing down. Just degrease, pressure wash, dry in the sun and two coats of paint brushed on about 30minutes apart. Leave it a couple of hours to dry in the sun before reassembling the machine. Polish the column first, and mask the bottom before painting the base.

For breaking stuck joints, I think fast heating rather than slow is required.

If the base is heated rapidly with a torch, the base starts expanding before any heat reaches the column, and the expansion pulls hard on the rust sticking them together. And if the base is then cooled quickly, it contracts and crushes the rust against the column. Both actions give the rust a hard time, which loosens the joint. Several hot-cold cycles may be needed.

Slowly heating the base and column together much reduces the stretch/crush action because the parts expand and contract at together at the same rate, giving the rust an easy ride.

Slow heating works if the joint is stuck by gummed oil, paint or loctite, which have to be burnt out.

Shock is more effective at breaking joints than a slow push with a hydraulic ram, but there's a risk of cracking cast-iron. Sharp raps with a big hammer often get stuff moving, though whacking stuff hard always makes me nervous! Anyone tried a jack hammer?

Dave

If it was originally a press fit, and you do manage to press it out, you'll eventually have to press it back in. This looks to be beyond the throat of your press. I'd buy 4 castors and a bit of plywood and make a trolley on which to move it around. I've got such a beast, and it's dead handy for all sorts of moving jobs. Last time was shifting a king size mattress, I could tip it on its side, but no way could I then drag it.